"I have been hesitating between two topics for historical investigation--Spanish history from the invasion of the Arabs to the consolidation of the monarchy under Charles V., or a history of the revolution of ancient Rome which converted the republic into an empire.... I shall probably select the first as less difficult of execution than the second." He also planned a collection of biographical sketches and criticisms, but presently rejected that, as he did, a year later, the Roman subject; and after having done so, the mists began to clear away and a great purpose to take shape before his mental vision. On January 8, 1826, he wrote a long memorandum which represents the focussing of his hitherto vague mental strivings. "Cannot I contrive to embrace the _gist_ of the Spanish subject without involving myself in the unwieldy barbarous records of a thousand years? What new and interesting topic may be admitted--not forced--into the reigns of Ferdinand and Isabella? Can I not indulge in a retrospective picture of the constitutions of Castile and Aragon--of the Moorish dynasties and the causes of their decay and dissolution? Then I have the Inquisition with its bloody persecutions; the conquest of Granada, a brilliant passage; the exploits of the Great Captain in Italy; ... the discovery of a new world, my own country.... A biography will make me responsible for a limited space only; will require much less reading; will offer the deeper interest which always attaches to minute developments of character, and the continuous, closely connected narratives. The subject brings me to a point whence [modern] English history has started, is untried ground, and in my opinion a rich one. The age of Ferdinand is most important.... It is in every respect an interesting and momentous period of history; the materials authentic, ample. I will chew upon this matter and decide this week." Long afterward (in 1847) Prescott pencilled upon this memorandum the words: "This was the first germ of my conception of _Ferdinand and Isabella_." On January 19th, after some further wavering, he wrote down definitely: "I subscribe to the _History of the Reign of Ferdinand and Isabella_." Opposite this note he made, in 1847, the brief but emphatic comment,--"A fortunate choice."